This invention is in the field of wheel chair construction and more particularly auxiliary drive means and the mounting thereof to wheel chairs. Wheel chairs are not particularly designed for use over long distances. As a result, various auxiliary drive means have been provided to increase the range of the wheel chair. In one form, a hand crank is provided which is operatively associated with the wheels by means of a chain. Three different versions are shown in the U.S. Pat. Nos. 3,485,510, issued to J. Merlan on Dec. 3, 1969; 3,994,509, issued to J. Schaeffer on Nov. 30, 1976 and 4,274,651, issued to H. H. Dumont on June 23, 1981. A similar tricycle arrangement is shown in the U.S. Pat. No. 4,109,927, issued to R. L. Harper on Aug. 29, 1978.
Typically, the drive means is designed to be removably mounted to the front vertical post of the wheel chair with a hand crank provided for use by the operator. Such a type is shown in the aforementioned U.S. Pat. No. 3,485,510 and is also available from Orthopedic Systems, Inc., Route 1, Box 136A, Nelsonville, Ohio 45764 and Fabrique Par:Unicycle Inc., 2143, Rue St.-Patrick, Montreal, Quebec, Canada.
Disclosed herein is an improved drive means over the latter mentioned drive means. The improved version disclosed herein is particularly advantageous in that it is easily mounted to and removed from a variety of different sized and configured wheel chairs. In U.S. Pat. No. 3,485,510, the drive means in an alternate embodiment includes a telescopic rod adjustable to fit different spacings of the vertical wheel chair posts. The adjustment means of the mounting structure disclosed herein includes an adjustable in line threaded member to facilitate different spacing of the wheel chair vertical post. Further, the steering post of the drive means may be pivoted and telescoped to the exact position of the person sitting in the wheel chair facilitating ease of use. A pair of continuous roller chains are used in lieu of the prior approach of using a single roller chain thereby enabling the hand crank to be more accurately positioned with respect to the user's hands.